Get id of div in parent document

I need to get the id of a div in the parent document of a开发者_StackOverflown iframed document. The actual scenario is I have a facebook application developed using FBML. The canvas page contains an iframe. If the user clicks on a button inside the iframed document, I need to display a div in the canvas page that is hidden when loading.

Thanks in advance...

did you try parent.document.getElementById('YOUR_ID'); ?

Are both documents (parent and iframe) in the same domain? If no, then browser doesn't allow you to access to parent document for security reasons.

EDIT: If both documents are in the same domain then you can access the element of parent document as follows:

var parentDoc = parent.document;
var el = parentDoc.getElementById("foobar");

try $(this).parent().attr('id')